draft-ietf-pce-disco-proto-ospf-00.txt   draft-ietf-pce-disco-proto-ospf-01.txt 
Network Working Group J.L. Le Roux (Editor) Network Working Group J.L. Le Roux (Editor)
Internet Draft France Telecom Internet Draft France Telecom
Category: Standard Track Category: Standard Track
Expires: March 2007 J.P. Vasseur (Editor) Expires: June 2007 J.P. Vasseur (Editor)
Cisco System Inc. Cisco System Inc.
Yuichi Ikejiri Yuichi Ikejiri
NTT Communications NTT Communications
Raymond Zhang Raymond Zhang
BT Infonet BT Infonet
September 2006 December 2006
OSPF protocol extensions for Path Computation Element (PCE) Discovery OSPF protocol extensions for Path Computation Element (PCE) Discovery
draft-ietf-pce-disco-proto-ospf-00.txt draft-ietf-pce-disco-proto-ospf-01.txt
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Abstract Abstract
There are various circumstances in which it is highly desirable for a There are various circumstances where it is highly desirable for a
Path Computation Client (PCC) to be able to dynamically and Path Computation Client (PCC) to be able to dynamically and
automatically discover a set of Path Computation Element(s) (PCE), automatically discover a set of Path Computation Element(s) (PCE),
along with some of information that can be used for PCE selection. along with some of information that can be used for PCE selection.
When the PCE is an LSR participating to the IGP, or even a server
participating passively to the IGP, a simple and efficient way for When the PCE is a Label Switch Router (LSR) participating to the IGP,
PCE discovery consists of relying on IGP flooding. For that purpose or even a server participating passively to the IGP, a simple and
this document defines OSPF extensions for the advertisement of PCE efficient way for PCE discovery consists of relying on IGP flooding.
Discovery information within an OSPF area or within the entire OSPF For that purpose this document defines OSPF extensions for the
routing domain. advertisement of PCE Discovery information within an OSPF area or
within the entire OSPF routing domain.
Conventions used in this document Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119. document are to be interpreted as described in RFC-2119.
Table of Contents Table of Contents
1. Note........................................................3 1. Note (to be removed before publication).....................3
2. Terminology.................................................3 2. Terminology.................................................3
3. Introduction................................................4 3. Introduction................................................4
4. Overview....................................................5 4. Overview....................................................5
4.1. PCE Information.............................................5 4.1. PCE Information.............................................5
4.1.1. PCE Discovery Information...................................5 4.1.1. PCE Discovery Information...................................5
4.1.2. PCE Status Information......................................6 4.1.2. PCE Status Information......................................6
4.2. Flooding scope..............................................6 4.2. Flooding scope..............................................6
5. OSPF extensions.............................................6 5. OSPF extensions.............................................6
5.1. The OSPF PCED TLV...........................................6 5.1. The OSPF PCED TLV...........................................6
5.1.1. PCE-ADDRESS sub-TLV.........................................7 5.1.1. PCE-ADDRESS sub-TLV.........................................8
5.1.2. PATH-SCOPE sub-TLV..........................................8 5.1.2. PATH-SCOPE sub-TLV..........................................8
5.1.3. PCE-DOMAINS sub-TLV........................................10 5.1.3. PCE-DOMAINS sub-TLV........................................10
5.1.3.1. IPv4 area ID DOMAIN sub-TLV..............................11 5.1.3.1. IPv4 area ID DOMAIN sub-TLV..............................11
5.1.3.2. IPv6 area ID DOMAIN sub-TLV..............................11 5.1.3.2. IPv6 area ID DOMAIN sub-TLV..............................12
5.1.3.3. AS Number sub-TLV........................................12 5.1.3.3. AS Number sub-TLV........................................12
5.1.4. PCE-DEST-DOMAINS sub-TLV...................................12 5.1.4. PCE-DEST-DOMAINS sub-TLV...................................12
5.1.5. GENERAL-CAP sub-TLV........................................13 5.1.5. GENERAL-CAP sub-TLV........................................13
5.1.6. The PATH-COMP-CAP sub-TLV..................................14 5.1.6. The PATH-COMP-CAP sub-TLV..................................14
5.1.6.1. Objective Functions sub-TLV..............................15 5.1.6.1. Objective Functions sub-TLV..............................16
5.1.6.2. Opaque Objective Function sub-TLV........................16 5.1.6.2. Opaque Objective Function sub-TLV........................16
5.1.6.3. Switch Caps sub-TLV......................................16 5.1.6.3. Switch Caps sub-TLV......................................17
5.2. The OSPF PCES TLV..........................................17 5.2. The OSPF PCES TLV..........................................17
5.2.1. The CONGESTION sub-TLV.....................................17 5.2.1. The CONGESTION sub-TLV.....................................18
6. Elements of Procedure......................................19 6. Elements of Procedure......................................19
6.1.1. PCES TLV specific procedures...............................19 6.1.1. PCES TLV specific procedures...............................20
7. Backward compatibility.....................................21 7. Backward compatibility.....................................20
8. IANA considerations........................................21 8. IANA considerations........................................21
8.1. OSPF TLVs..................................................21 8.1. OSPF TLVs..................................................21
8.2. Capability bits............................................21 8.2. Capability bits............................................22
9. Security Considerations....................................22 9. Security Considerations....................................22
10. References.................................................22 10. Manageability Considerations...............................23
10.1. Normative references.......................................22 11. Acknowledgments............................................23
10.2. Informative references.....................................23 12. References.................................................23
11. Authors' Addresses:........................................23 12.1. Normative references.......................................23
12. Intellectual Property Statement............................24 12.2. Informative references.....................................24
13. Editor's Addresses:........................................24
14. Contributors' Addresses:...................................24
15. Intellectual Property Statement............................24
1. Note 1. Note (to be removed before publication)
This document specifies new TLVs and sub-TLVs to be carried within This document specifies new TLVs and sub-TLVs to be carried within
the OSPF Router information LSA ([OSPF-CAP]). Because this document the OSPF Router information LSA ([OSPF-CAP]). Because this document
does not introduce any new element of procedure it will be discussed does not introduce any new element of procedure it will be discussed
within the PCE Working Group with a review of the OSPF Working Group. within the PCE Working Group with a review of the OSPF Working Group.
2. Terminology 2. Terminology
Terminology used in this document Terminology used in this document
ABR: IGP Area Border Router. ABR: IGP Area Border Router.
AS: Autonomous System. AS: Autonomous System.
ASBR: AS Border Router.
Domain: any collection of network elements within a common sphere Domain: any collection of network elements within a common sphere
of address management or path computational responsibility. of address management or path computational responsibility.
Examples of domains include IGP areas and Autonomous Systems. Examples of domains include IGP areas and Autonomous Systems.
Intra-area TE LSP: A TE LSP whose path does not cross IGP area Intra-area TE LSP: A TE LSP whose path does not cross IGP area
boundaries. boundaries.
Intra-AS TE LSP: A TE LSP whose path does not cross AS boundaries. Intra-AS TE LSP: A TE LSP whose path does not cross AS boundaries.
Inter-area TE LSP: A TE LSP whose path transits through Inter-area TE LSP: A TE LSP whose path transits through
two or more IGP areas. two or more IGP areas.
Inter-AS MPLS TE LSP: A TE LSP whose path transits Inter-AS TE LSP: A TE LSP whose path transits through two or more
through two or more ASes or sub-ASes (BGP confederations). ASes or sub-ASes (BGP confederations).
LSR: Label Switch Router. LSR: Label Switch Router.
PCC: Path Computation Client: any client application requesting a PCC: Path Computation Client: any client application requesting a
path computation to be performed by a Path Computation Element. path computation to be performed by a Path Computation Element.
PCE: Path Computation Element: an entity (component, application, PCE: Path Computation Element: an entity (component, application,
or network node) that is capable of computing a network path or or network node) that is capable of computing a network path or
route based on a network graph, and applying computational route based on a network graph, and applying computational
constraints. constraints.
PCECP: Path Computation Element Communication Protocol. PCEP: Path Computation Element Protocol.
TE LSP: Traffic Engineered Label Switched Path. TE LSP: Traffic Engineered Label Switched Path.
3. Introduction 3. Introduction
[RFC4655] describes the motivations and architecture for a PCE-based [RFC4655] describes the motivations and architecture for a PCE-based
path computation model for MPLS and GMPLS TE LSPs. The model allows path computation model for Multi Protocol Label Switching (MPLS) and
the separation of PCE from PCC (also referred to as non co-located Generalized MPLS (GMPLS) Traffic Engineered Label Switched Paths (TE-
PCE) and allows cooperation between PCEs. This relies on a LSPs). The model allows for the separation of PCE from PCC (also
communication protocol between PCC and PCE, and between PCEs. The referred to as non co-located PCE) and allows for cooperation between
requirements for such communication protocol can be found in [PCECP- PCEs. This relies on a communication protocol between PCC and PCE,
REQ] and the communication protocol is defined in [PCEP]. and between PCEs. The requirements for such communication protocol
can be found in [RFC4657] and the communication protocol is defined
in [PCEP].
The PCE architecture requires, of course, that a PCC be aware of the The PCE architecture requires, of course, that a PCC be aware of the
location of one or more PCEs in its domain, and also potentially of location of one or more PCEs in its domain, and also potentially of
some PCEs in other domains, e.g. in case of inter-domain TE LSP some PCEs in other domains, e.g. in case of inter-domain TE LSP
computation. computation.
A network may comprise a large number of PCEs with potentially A network may comprise a large number of PCEs with potentially
distinct capabilities. In such context it would be highly desirable distinct capabilities. In such context it is highly desirable to have
to have a mechanism for automatic and dynamic PCE discovery, which a mechanism for automatic and dynamic PCE discovery, which allows
would allow PCCs to automatically discover a set of PCEs, along with PCCs to automatically discover a set of PCEs, along with additional
additional information required for PCE selection, and to dynamically information required for PCE selection, and to dynamically detect new
detect new PCEs or any modification of PCE information. PCEs or any modification of PCE information. Detailed requirements
Detailed requirements for such a PCE discovery mechanism are for such a PCE discovery mechanism are described in [RFC4674].
described in [PCE-DISC-REQ].
Moreover, it may also be useful to discover when a PCE experiences Moreover, it may also be useful to discover when a PCE experiences
some processing congestion state and exits such state, in order for some processing congestion state and exits such state, in order for
the PCCs to take some appropriate actions (e.g. redirect to another the PCCs to take some appropriate actions (e.g. redirect to another
PCE). Note that the PCE selection algorithm is out of the scope of PCE). Note that the PCE selection algorithm is out of the scope of
this document. this document.
When PCCs are LSRs participating to the IGP, and PCEs are LSRs or a When PCCs are LSRs participating to the IGP (OSPF or IS-IS), and PCEs
servers also participating to the IGP, an efficient mechanism for PCE are LSRs or a servers also participating to the IGP, an efficient
discovery within an IGP routing domain consists of relying on IGP mechanism for PCE discovery within an IGP routing domain consists of
advertisements. relying on IGP advertisements.
This document defines OSPF extensions allowing a PCE in the OSPF This document defines OSPF extensions allowing a PCE in the OSPF
routing domain to advertise its location along with some information routing domain to advertise its location along with some information
useful for PCE selection so as to satisfy dynamic PCE discovery useful for PCE selection so as to satisfy dynamic PCE discovery
requirements set forth in [PCE-DISC-REQ]. This document also defines requirements set forth in [RFC4674]. This document also defines
extensions allowing a PCE in the OSPF routing domain to advertise its extensions allowing a PCE in the OSPF routing domain to advertise its
potential processing congestion state. potential processing congestion state.
Generic capability mechanisms for OSPF have been defined in [OSPF- Generic capability mechanisms for OSPF have been defined in [OSPF-
CAP] the purpose of which is to allow a router to advertise its CAP] the purpose of which is to allow a router to advertise its
capability within an OSPF area or an entire OSPF routing domain. Such capability within an OSPF area or an entire OSPF routing domain. Such
OSFP extensions fully satisfy the aforementioned dynamic PCE OSFP extensions fully satisfy the aforementioned dynamic PCE
discovery requirements. discovery requirements.
This document defines two new sub-TLVs (named the PCE Discovery This document defines two new sub-TLVs (named the PCE Discovery
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extensions and procedures are defined in section 5 and 6. extensions and procedures are defined in section 5 and 6.
This document does not define any new OSPF element of procedure but This document does not define any new OSPF element of procedure but
how the procedures defined in [OSPF-CAP] should be used. how the procedures defined in [OSPF-CAP] should be used.
The routing extensions defined in this document allow for PCE The routing extensions defined in this document allow for PCE
discovery within an OSPF Routing domain. Solutions for PCE discovery discovery within an OSPF Routing domain. Solutions for PCE discovery
across AS boundaries are beyond the scope of this document, and for across AS boundaries are beyond the scope of this document, and for
further study. further study.
Similar extensions to ISIS for PCE discovery can be found in [ISIS- In this document, we call TLV any TLV that is carried within an OSPF
PCE-DISCO]. LSA. We call indifferently TLV or sub-TLV, any TLV that is itself
carried within another TLV.
4. Overview 4. Overview
4.1. PCE Information 4.1. PCE Information
PCE information advertised within the IGP includes PCE Discovery The PCE information advertised via OSPF falls into two categories:
Information and PCE Status information. PCE Discovery Information and PCE Status information.
4.1.1. PCE Discovery Information 4.1.1. PCE Discovery Information
The PCE Discovery information is comprised of: The PCE Discovery information is comprised of:
- The PCE location: This an IPv4 and/or IPv6 address that must be - The PCE location: an IPv4 and/or IPv6 address that must be
used to reach the PCE. It is RECOMMENDED to use addresses always used to reach the PCE. It is RECOMMENDED to use addresses always
reachable; reachable;
- The PCE inter-domain functions: this refers to the PCE path - The PCE inter-domain functions: PCE path computation scope (i.e.
computation scope (i.e. inter-area, inter-AS, inter-layer…); inter-area, inter-AS, inter-layer…);
- The PCE domain(s): This is the set of one or more domain(s) where - The PCE domain(s): the set of one or more domain(s) where
the PCE has visibility and can compute paths; the PCE has visibility and can compute paths;
- The PCE Destination domain(s): This is the set of one or more - The PCE Destination domain(s): set of one or more destination
destination domain(s) towards which a PCE can compute paths; domain(s) towards which a PCE can compute paths;
- A set of general PCECP capabilities (e.g. support for request - A set of general PCEP capabilities (e.g. support for request
prioritization) and path computation specific capabilities prioritization) and path computation specific capabilities
(e.g. supported constraints, supported objective functions). (e.g. supported constraints, supported objective functions).
It may also contain optional elements to describe more complex Optional elements to describe more complex capabilities may also be
capabilities. advertised.
PCE Discovery information is by nature a static information that does PCE Discovery information is by nature fairly static and does not
not change with PCE activity. Changes in PCE Discovery information change with PCE activity. Changes in PCE Discovery information may
may occur as a result of PCE configuration updates, PCE occur as a result of PCE configuration updates, PCE
deployment/activation, PCE deactivation/suppression or PCE failure. deployment/activation, PCE deactivation/suppression or PCE failure.
Hence, this information is not expected to change frequently. Hence, this information is not expected to change frequently.
4.1.2. PCE Status Information 4.1.2. PCE Status Information
The PCE Status is optional information that can be used to report a The PCE Status is optional information and can be used to report a
PCE processing congested state along with an estimated congestion PCE processing congested state along with an estimated congestion
duration. This is a dynamic information, which may change with PCE duration. This is a dynamic information, which may change with PCE
activity. activity.
Procedures for a PCE to move from a processing congested state to a Procedures for a PCE to move from a processing congested state to a
non congested state are beyond the scope of this document, but the non congested state are beyond the scope of this document, but the
rate at which a PCE Status change is advertised MUST not impact by rate at which a PCE Status change is advertised MUST not impact by
any mean the IGP scalability. Particular attention should be given on any mean the IGP scalability. Particular attention should be given on
procedures to avoid state oscillations. procedures to avoid state oscillations.
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5. OSPF extensions 5. OSPF extensions
5.1. The OSPF PCED TLV 5.1. The OSPF PCED TLV
The OSPF PCE Discovery TLV (PCED TLV) is made of a set of non-ordered The OSPF PCE Discovery TLV (PCED TLV) is made of a set of non-ordered
sub-TLVs. sub-TLVs.
The format of the OSPF PCED TLV and its sub-TLVs is the identical as The format of the OSPF PCED TLV and its sub-TLVs is the identical as
the TLV format used by the Traffic Engineering Extensions to OSPF the TLV format used by the Traffic Engineering Extensions to OSPF
[OSPF-TE]. That is, the TLV is composed of 2 octets for the type, 2 [RFC3630]. That is, the TLV is composed of 2 octets for the type, 2
octets specifying the TLV length and a value field. The Length field octets specifying the TLV length and a value field. The Length field
defines the length of the value portion in octets. defines the length of the value portion in octets.
The TLV is padded to four-octet alignment; padding is not included in The TLV is padded to four-octet alignment; padding is not included in
the length field (so a three octet value would have a length of the length field (so a three octet value would have a length of
three, but the total size of the TLV would be eight octets). Nested three, but the total size of the TLV would be eight octets). Nested
TLVs are also 32-bit aligned. Unrecognized types are ignored. All TLVs are also 32-bit aligned. Unrecognized types are ignored. All
types between 32768 and 65535 are reserved for vendor-specific types between 32768 and 65535 are reserved for vendor-specific
extensions. All other undefined type codes are reserved for future extensions. All other undefined type codes are reserved for future
assignment by IANA. assignment by IANA.
The OSPF PCED TLV has the following format: The OSPF PCED TLV has the following format:
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Currently five sub-TLVs are defined (type values to be assigned by Currently five sub-TLVs are defined (type values to be assigned by
IANA): IANA):
Sub-TLV type Length Name Sub-TLV type Length Name
1 variable PCE-ADDRESS sub-TLV 1 variable PCE-ADDRESS sub-TLV
2 4 PATH-SCOPE sub-TLV 2 4 PATH-SCOPE sub-TLV
3 variable PCE-DOMAINS sub-TLV 3 variable PCE-DOMAINS sub-TLV
4 variable PCE-DEST-DOMAINS sub-TLV 4 variable PCE-DEST-DOMAINS sub-TLV
5 variable GENERAL-CAP sub-TLV 5 variable GENERAL-CAP sub-TLV
6 variable PATH-COMP-CAP sub-TLV 6 variable PATH-COMP-CAP sub-TLV
The sub-TLVs PCE-ADDRESS and PATH SCOPE MUST always be present within The PCE-ADDRESS and PATH-SCOPE sub-TLVs MUST always be present within
the PCED TLV. the PCED TLV.
The sub-TLVs PCE-DOMAINS and PCE-DEST-DOMAINS are optional. They MAY The PCE-DOMAINS and PCE-DEST-DOMAINS sub-TLVs are optional. They MAY
be present in some specific inter-domain cases. be present in the PCED TLV to facilitate selection of inter-domain
PCEs.
The GENERAL-CAP and PATH-COMP-CAP sub-TLVs are optional and MAY be The GENERAL-CAP and PATH-COMP-CAP sub-TLVs are optional and MAY be
present in the PCED TLV to facilitate the PCE selection process. present in the PCED TLV to facilitate the PCE selection process.
Any non recognized sub-TLV MUST be silently ignored. Any non recognized sub-TLV MUST be silently ignored.
Additional sub-TLVs could be added in the future to advertise Additional sub-TLVs could be added in the future to advertise
additional information. additional information.
The PCED TLV is carried within an OSPF Router Information LSA The PCED TLV is carried within an OSPF Router Information LSA
defined in [OSPF-CAP]. defined in [OSPF-CAP].
5.1.1. PCE-ADDRESS sub-TLV 5.1.1. PCE-ADDRESS sub-TLV
The PCE-ADDRESS sub-TLV specifies the IP address(es) that MUST be The PCE-ADDRESS sub-TLV specifies the IP address(es) that MUST be
used to reach the PCE. It is RECOMMENDED to make use of an address used to reach the PCE. It is RECOMMENDED to make use of an address
that is always reachable, provided that the PCE is alive. that is always reachable, provided that the PCE is alive.
The PCE-ADDRESS sub-TLV is mandatory; it MUST be present within the The PCE-ADDRESS sub-TLV is mandatory; it MUST be present within the
PCED TLV. It MAY appear twice, when the PCE has both an IPv4 and IPv6 PCED TLV. It MAY appear twice, when the PCE has both an IPv4 and IPv6
address. It MUST not appear more than twice. address. It MUST NOT appear more than once for the same address type.
The format of the PCE-ADDRESS sub-TLV is as follows: The format of the PCE-ADDRESS sub-TLV is as follows:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| address-type | Reserved | | address-type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
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setting up PCC-PCE communication sessions. setting up PCC-PCE communication sessions.
5.1.2. PATH-SCOPE sub-TLV 5.1.2. PATH-SCOPE sub-TLV
The PATH-SCOPE sub-TLV indicates the PCE path computation scope(s), The PATH-SCOPE sub-TLV indicates the PCE path computation scope(s),
which refers to the PCE ability to compute or take part into the which refers to the PCE ability to compute or take part into the
computation of intra-area, inter-area, inter-AS or inter-layer_TE computation of intra-area, inter-area, inter-AS or inter-layer_TE
LSP(s). LSP(s).
The PATH-SCOPE sub-TLV is mandatory; it MUST be present within the The PATH-SCOPE sub-TLV is mandatory; it MUST be present within the
PCED TLV. There MUST be exactly one PATH-SCOPE sub-TLV within each PCED TLV. There MUST be exactly one instance of the PATH-SCOPE sub-
PCED TLV. TLV within each PCED TLV.
The PATH-SCOPE sub-TLV contains a set of bit flags indicating the The PATH-SCOPE sub-TLV contains a set of bit flags indicating the
supported path scopes (intra-area, inter-area, inter-AS, inter-layer) supported path scopes (intra-area, inter-area, inter-AS, inter-layer)
and four fields indicating PCE preferences. and four fields indicating PCE preferences.
The PATH-SCOPE sub-TLV has the following format: The PATH-SCOPE sub-TLV has the following format:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|1|2|3|4|5| Reserved |PrefL|PrefR|PrefS|PrefY| Res | |0|1|2|3|4|5| Reserved |PrefL|PrefR|PrefS|PrefY| Res |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type To be defined by IANA (suggested value =3)
Type To be defined by IANA (suggested value =2)
Length Variable Length Variable
Value This comprises a 2 bytes flag where each bit Value This comprises a 2 bytes flag where each bit
represents a supported path scope, as well as four represents a supported path scope, as well as four
preference fields allowing to specify PCE preferences. preference fields used to specify PCE preferences.
The following bits are defined: The following bits are defined:
Bit Path Scope Bit Path Scope
0 L bit: Can compute intra-area path 0 L bit: Can compute intra-area path
1 R bit: Can act as PCE for inter-area TE LSPs 1 R bit: Can act as PCE for inter-area TE LSPs
computation computation
2 Rd bit: Can act as a default PCE for inter-area TE LSPs 2 Rd bit: Can act as a default PCE for inter-area TE LSPs
computation computation
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When set the Rd bit indicates that the PCE can act as a default PCE When set the Rd bit indicates that the PCE can act as a default PCE
for inter-area TE LSPs computation (the PCE can compute path for any for inter-area TE LSPs computation (the PCE can compute path for any
destination area). Similarly, when set the Sd bit indicates that the destination area). Similarly, when set the Sd bit indicates that the
PCE can act as a default PCE for inter-AS TE LSPs computation (the PCE can act as a default PCE for inter-AS TE LSPs computation (the
PCE can compute path for any destination AS). PCE can compute path for any destination AS).
When the Rd bit is set the PCE-DEST-DOMAIN TLV (see 5.1.4) does not When the Rd bit is set the PCE-DEST-DOMAIN TLV (see 5.1.4) does not
contain any Area ID DOMAIN sub-TLV. contain any Area ID DOMAIN sub-TLV.
Similarly, when the Sd bit is set the PCE-DEST-DOMAIN TLV does not Similarly, when the Sd bit is set the PCE-DEST-DOMAIN TLV does not
contain any AS DOMAIN sub-TLV. contain any AS-DOMAIN sub-TLV.
The PrefL, PrefR, PrefS and PrefY fields are 3-bit long and allow the The PrefL, PrefR, PrefS and PrefY fields are 3-bit long and allow the
PCE to specify a preference for each computation scope, where 7 PCE to specify a preference for each computation scope, where 7
reflects the highest preference. Such preference can be used for reflects the highest preference. Such preference can be used for
weighted load balancing of requests. An operator may decide to weighted load balancing of requests. An operator may decide to
configure a preference to each PCE so as to balance the path configure a preference to each PCE so as to balance the path
computation load among them, with respect to their respective CPU computation load among them, with respect to their respective CPU
capacity. The algorithms used by a PCC to load balance its path capacity. The algorithms used by a PCC to load balance its path
computation requests according to such PCE’s preference is out of the computation requests according to such PCE’s preference is out of the
scope of this document. Same or distinct preferences may be used for scope of this document. Same or distinct preferences may be used for
different scopes. For instance an operator that wants a PCE capable different scopes. For instance an operator that wants a PCE capable
of both inter-area and inter-AS computation to be used preferably for of both inter-area and inter-AS computation to be used preferably for
inter-AS computation may configure a PrefS higher than the PrefR. inter-AS computation may configure a PrefS higher than the PrefR.
When the PrefL, PrefR, PRefS or PrefY is cleared, this indicates an
absence of preference.
When the L bit, R bit, S or Y bit are cleared, the PrefL, PrefR, When the L bit, R bit, S or Y bit are cleared, the PrefL, PrefR,
PrefS, PrefY fields MUST respectively be set to 0. PrefS, PrefY fields MUST respectively be set to 0.
5.1.3. PCE-DOMAINS sub-TLV 5.1.3. PCE-DOMAINS sub-TLV
The PCE-DOMAINS sub-TLV specifies the set of domains (areas, AS) The PCE-DOMAINS sub-TLV specifies the set of domains (areas, AS)
where the PCE has topology visibility and can compute paths. It where the PCE has topology visibility and can compute paths. It
contains a set of one or more sub-TLVs where each sub-TLV identifies contains a set of one or more sub-TLVs where each sub-TLV identifies
a domain. a domain.
The PCED TLV MUST include zero or one PCE-DOMAINS sub-TLV. The PCED TLV MUST include zero or one PCE-DOMAINS sub-TLV.
The PCE-DOMAINS sub-TLV MUST be present when PCE domains cannot be The PCE-DOMAINS sub-TLV MUST be present when PCE domains cannot be
inferred by other IGP information, for instance when the PCE is inferred by other IGP information, for instance when the PCE is
inter-area capable (i.e. when the R bit is set) and the flooding inter-domain capable (i.e. when the R bit or S bit is set) and the
scope is the entire OSPF routing domain. flooding scope is the entire OSPF routing domain.
The PCE-DOMAINS sub-TLV has the following format: The PCE-DOMAINS sub-TLV has the following format:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// DOMAIN sub-TLVs // // DOMAIN sub-TLVs //
| | | |
skipping to change at page 12, line 27 skipping to change at page 12, line 46
Type To be assigned by IANA (suggested value =3) Type To be assigned by IANA (suggested value =3)
Length 4 Length 4
AS Number: AS number identifying an AS. When coded on two AS Number: AS number identifying an AS. When coded on two
bytes (which is the current defined format as the bytes (which is the current defined format as the
time of writing this document), the AS Number field time of writing this document), the AS Number field
MUST have its left two bytes set to 0. MUST have its left two bytes set to 0.
5.1.4. PCE-DEST-DOMAINS sub-TLV 5.1.4. PCE-DEST-DOMAINS sub-TLV
The PCE-DEST-DOMAINS sub-TLV specifies the set of destination domains The PCE-DEST-DOMAINS sub-TLV specifies the set of destination domains
(areas, AS) toward which a PCE can compute path. It means that the (areas, AS) toward which a PCE can compute paths. It means that the
PCE can compute or take part in the computation of inter-domain LSPs PCE can compute or take part in the computation of inter-domain LSPs
whose destinations are located within one of these domains. It whose destinations are located within one of these domains. It
contains a set of one or more sub-TLVs where each sub-TLV identifies contains a set of one or more sub-TLVs where each sub-TLV identifies
a domain. a domain.
The PCE-DEST-DOMAINS sub-TLV has the following format: The PCE-DEST-DOMAINS sub-TLV has the following format:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
skipping to change at page 13, line 14 skipping to change at page 13, line 35
The PCE-DEST-DOMAINS sub-TLV MUST include at least one DOMAIN sub- The PCE-DEST-DOMAINS sub-TLV MUST include at least one DOMAIN sub-
TLV. It MUST include at least one area ID sub-TLV, if the R bit of TLV. It MUST include at least one area ID sub-TLV, if the R bit of
the PATH-SCOPE TLV is set and the Rd bit of the PATH-SCOPE TLV is the PATH-SCOPE TLV is set and the Rd bit of the PATH-SCOPE TLV is
cleared. Similarly, it MUST include at least one AS number sub-TLV if cleared. Similarly, it MUST include at least one AS number sub-TLV if
the S bit of the PATH-SCOPE TLV is set and the Sd bit of the PATH- the S bit of the PATH-SCOPE TLV is set and the Sd bit of the PATH-
SCOPE TLV is cleared. SCOPE TLV is cleared.
5.1.5. GENERAL-CAP sub-TLV 5.1.5. GENERAL-CAP sub-TLV
The GENERAL-CAP sub-TLV is an optional TLV used to indicate PCECP The GENERAL-CAP sub-TLV is an optional TLV used to indicate PCEP
related capabilities. It MAY be present within the PCED TLV. It MUST related capabilities. It MAY be present within the PCED TLV. It MUST
not be present more than once. not be present more than once.
The value field of the GENERAL-CAP sub-TLV is made of a 32-bit flag, The value field of the GENERAL-CAP sub-TLV is made of a 32-bit flag,
where each bit corresponds to a general PCE capability. It MAY also where each bit corresponds to a general PCE capability. It MAY also
include optional sub-TLVs to encode more complex capabilities. include optional sub-TLVs to encode more complex capabilities.
The format of the GENERAL-CAP sub-TLV is as follows: The format of the GENERAL-CAP sub-TLV is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 14, line 7 skipping to change at page 14, line 28
Bit Capabilities Bit Capabilities
0 P bit: Support for Request prioritization. 0 P bit: Support for Request prioritization.
1 M bit: Support for multiple messages within the same 1 M bit: Support for multiple messages within the same
request message. request message.
2-31 Reserved for future assignments by IANA. 2-31 Reserved for future assignments by IANA.
5.1.6. The PATH-COMP-CAP sub-TLV 5.1.6. The PATH-COMP-CAP sub-TLV
The PATH-COMP-CAP sub-TLV is an optional TLV used to indicate path The PATH-COMP-CAP sub-TLV is an optional sub-TLV used to indicate
computation specific capabilities. It MAY be present within the PCED path computation specific capabilities. It MAY be present within the
TLV. It MUST not be present more than once. PCED TLV. It MUST not be present more than once.
It is made of a 32-bit flag, where each bit corresponds to a path It is made of a 32-bit flag, where each bit corresponds to a path
computation capability. It MAY also include optional sub-TLVs to computation capability. It MAY also include optional sub-TLVs to
encode more complex capabilities. encode more complex capabilities.
The format of the PATH-COMP-CAP sub-TLV is as follows: The format of the PATH-COMP-CAP sub-TLV is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
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information. information.
Sub-TLV types are under IANA control. Sub-TLV types are under IANA control.
Currently two sub-TLVs are defined (type values to be assigned by Currently two sub-TLVs are defined (type values to be assigned by
IANA): IANA):
Sub-TLV type Length Name Sub-TLV type Length Name
1 variable PCE-ADDRESS sub-TLV 1 variable PCE-ADDRESS sub-TLV
2 4 CONGESTION sub-TLV 2 4 CONGESTION sub-TLV
The PCE-ADDRESS and CONGESTION sub-TLVs MUST be present once There MUST be exactly one occurrence of the PCE-ADDRESS and
in a PCES TLV. The PCE-ADDRESS sub-TLV is defined in section 5.1.1. CONGESTION sub-TLVs within a PCES TLV. The PCE-ADDRESS sub-TLV is
defined in section 5.1.1.
It carries one of the PCE IP addresses and is used to identify the It carries one of the PCE IP addresses and is used to identify the
PCE the processing congestion state information is applied to. This PCE experiencing a processing congestion state. This
is required as the PCES and PCED TLVs may be carried in separate is required as the PCES and PCED TLVs may be carried in separate
Router Information LSAs. Router Information LSAs.A PCE implementation MUST use the same IP
address for the PCE-ADDRESS sub-TLV carried within the PCED TLV and
the PCE-ADDRESS TLV carried within the PCES sub-TLV.
Any non recognized sub-TLV MUST be silently ignored. Any non recognized sub-TLV MUST be silently ignored.
Additional sub-TLVs could be added in the future to advertise Additional sub-TLVs could be added in the future to advertise
additional congestion information. additional congestion information.
5.2.1. The CONGESTION sub-TLV 5.2.1. The CONGESTION sub-TLV
The CONGESTION sub-TLV is used to indicate whether a PCE experiences The CONGESTION sub-TLV is used to indicate whether a PCE experiences
a processing congestion state or not along with optionally the a processing congestion state or not along with optionally the
expected PCE congestion duration. expected PCE congestion duration.
The CONGESTION sub-TLV is mandatory. It MUST be carried once within The CONGESTION sub-TLV is mandatory. There MUST be a single instance
the PCES TLV. of the CONGESTION sub-TLV within the PCES TLV.
The format of the CONGESTION sub-TLV is as follows: The format of the CONGESTION sub-TLV is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C| Reserved | Congestion Duration | |C| Reserved | Congestion Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type To be assigned by IANA (suggested value =2) Type To be assigned by IANA (suggested value =2)
Length 4 Length 4
Value Value
-C bit: When set this indicates that the PCE experiences -C bit: When set this indicates that the PCE experiences
congestion and cannot support any new request. When congestion and cannot accept any new request. When
cleared this indicates that the PCE does not cleared this indicates that the PCE does not
experience congestion an can support a new request. experience congestion and can accept new requests.
-Congestion Duration: 2-bytes, the estimated PCE congestion -Congestion Duration: 2-bytes, the estimated PCE congestion
duration in seconds. duration in seconds.
When C is set and the Congestion Duration field is equal to 0, this When C is set and the Congestion Duration field is equal to 0, this
means that the Congestion Duration is unknown. means that the Congestion Duration is unknown.
When C is cleared the Congestion Duration MUST be set to 0. When C is cleared the Congestion Duration MUST be set to 0.
6. Elements of Procedure 6. Elements of Procedure
skipping to change at page 19, line 20 skipping to change at page 19, line 30
[OSPF-CAP]. As such, elements of procedure are inherited [OSPF-CAP]. As such, elements of procedure are inherited
from those defined in [OSPF-CAP]. from those defined in [OSPF-CAP].
As the PCES information is likely to change more frequently than the As the PCES information is likely to change more frequently than the
PCED information, it is RECOMMENDED to carry PCES and PCED TLVs in PCED information, it is RECOMMENDED to carry PCES and PCED TLVs in
separate Router Information LSAs, so as not to carry all PCED separate Router Information LSAs, so as not to carry all PCED
information each time the PCE status changes. information each time the PCE status changes.
In OSPFv2 the flooding scope is controlled by the opaque LSA type (as In OSPFv2 the flooding scope is controlled by the opaque LSA type (as
defined in [RFC2370]) and in OSPFv3 by the S1/S2 bits (as defined in defined in [RFC2370]) and in OSPFv3 by the S1/S2 bits (as defined in
[OSPF-v3]). If the flooding scope is local to an area then the PCED [RFC2740]). If the flooding scope is local to an area then the PCED
or PCES TLV MUST be carried within an OSPFv2 type 10 router or PCES TLV MUST be carried within an OSPFv2 type 10 router
information LSA or an OSPFV3 Router Information LSA with the S1 bit information LSA or an OSPFV3 Router Information LSA with the S1 bit
set and the S2 bit cleared. If the flooding scope is the entire set and the S2 bit cleared. If the flooding scope is the entire
domain then the PCED or PCES TLV MUST be carried within an OSPFv2 domain then the PCED or PCES TLV MUST be carried within an OSPFv2
type 11 Router Information LSA or OSPFv3 Router Information LSA with type 11 Router Information LSA or OSPFv3 Router Information LSA with
the S1 bit cleared and the S2 bit set. the S1 bit cleared and the S2 bit set.
Note that when only the L bit of the PATH-SCOPE sub-TLV is set and When only the L bit of the PATH-SCOPE sub-TLV is set, the flooding
the flooding scope MUST be local. scope MUST be local.
Note that the flooding scope of the PCED and PCES TLVs may be Note that the flooding scope of the PCED and PCES TLVs may be
distinct, in which case they will be carried in separate LSA. distinct, in which case they will be carried in separate LSA.
A router MUST originate a new OSPF router information LSA whenever A router MUST originate a new OSPF router information LSA whenever
the content of the PCED TLV or PCES TLV changes or whenever required the content of the PCED TLV or PCES TLV changes or whenever required
by the regular OSPF procedure (LSA refresh (every LSRefreshTime)). by the regular OSPF procedure (LSA refresh (every LSRefreshTime)).
PCED and PCES sub-TLVs are OPTIONAL. When an OSPF LSA does not PCED and PCES sub-TLVs are OPTIONAL. When an OSPF LSA does not
contain any PCED or PCES sub-TLV, this means that the PCE information contain any PCED or PCES sub-TLV, this means that the PCE information
of that node is unknown. of that node is unknown.
Note that a change in PCED or PCES information MUST not trigger any A change in PCED or PCES information MUST not trigger any
SPF computation. SPF computation.
The way PCEs retrieve their own information is out of the scope of The way PCEs retrieve their own information is out of the scope of
this document. Some information may be configured on the PCE (e.g. this document. Some information may be configured on the PCE (e.g.
address, preferences, scope) and other information may be address, preferences, scope) and other information may be
automatically retrieved by the PCE (e.g. areas of visibility). automatically retrieved by the PCE (e.g. areas of visibility).
6.1.1. PCES TLV specific procedures 6.1.1. PCES TLV specific procedures
When a PCE enters into a processing congestion state, the conditions When a PCE enters into a processing congestion state, the conditions
of which are implementation dependent, it SHOULD originate a Router of which are implementation dependent, it SHOULD originate a Router
Information LSA with a PCES TLV with the C bit set, and optionally a Information LSA with a PCES TLV with the C bit set, and optionally a
non-null expected congestion duration. non-null expected congestion duration.
When a PCE leaves the processing congestion state, the conditions of When a PCE exits from the processing congestion state, the conditions
which are implementation dependent, there are two cases: of which are implementation dependent, two cases are considered:
- If the congestion duration in the previously originated PCES - If the congestion duration in the previously originated PCES
TLV was null, it SHOULD originate a PCES TLV with the C bit cleared TLV was null, it SHOULD originate a PCES TLV with the C bit cleared
and a null congestion duration; and a null congestion duration;
- If the congestion duration in the previously originated PCES - If the congestion duration in the previously originated PCES
TLV was non null, it MAY originate a PCES TLV. Note that in some TLV was non null, it MAY originate a PCES TLV. Note that in some
particular cases it may be desired to originate a PCES TLV with the C particular cases it may be desired to originate a PCES TLV with the C
bit cleared if the saturation duration was over estimated. bit cleared if the congestion duration was over estimated.
The congestion duration allows reducing the amount of OSPF flooding, The congestion duration allows reducing the amount of OSPF flooding,
as only uncongested-congested state transitions are flooded. as only uncongested-to-congested state transitions are advertised.
An implementation SHOULD support an appropriate dampening algorithm An implementation SHOULD support an appropriate dampening algorithm
so as to dampen OSPF flooding in order to not impact the OSPF so as to dampen OSPF flooding in order to not impact the OSPF
scalability. It is RECOMMENDED to introduce some hysteresis for scalability. It is RECOMMENDED to introduce some hysteresis for
congestion state transition, so as to avoid state oscillations that congestion state transition, so as to avoid state oscillations that
may impact OSPF performances. For instance two thresholds MAY be may impact OSPF performances. For instance two thresholds MAY be
configured: A resource saturation upper-threshold and a resource configured: A resource congestion upper-threshold and a resource
saturation lower-threshold. An LSR enters the congested state when congestion lower-threshold. An LSR enters the congested state when
the CPU load reaches the upper threshold and leaves the congested the CPU load reaches the upper threshold and leaves the congested
state when the CPU load goes under the lower threshold. state when the CPU load goes under the lower threshold.
Upon receipt of an updated PCES TLV a PCC should take appropriate Upon receipt of an updated PCES TLV a PCC should take appropriate
actions. In particular, the PCC SHOULD stop sending requests to a actions. In particular, the PCC SHOULD stop sending requests to a
congested PCE, and SHOULD gradually start sending again requests to a congested PCE, and SHOULD gradually start sending again requests to a
no longer congested PCE. no longer congested PCE.
7. Backward compatibility 7. Backward compatibility
The PCED and PCES TLVs defined in this document do not introduce any The PCED and PCES TLVs defined in this document do not introduce any
interoperability issue. interoperability issue.
A router not supporting the PCED/PCES TLVs SHOULD just silently A router not supporting the PCED/PCES TLVs will just silently ignore
ignore the TLVs as specified in [OSPF-CAP]. the TLVs as specified in [OSPF-CAP].
8. IANA considerations 8. IANA considerations
8.1. OSPF TLVs 8.1. OSPF TLVs
IANA will assign a new codepoint for the OSPF PCED TLV defined in IANA will assign two new codepoints for the PCED and PCES sub-TLVs
this document and carried within the Router Information LSA. carried within the Router Information LSA defined in [OSPF-CAP].
Type Description Reference
1 PCED [OSPF-CAP]
2 PCES [OSPF-CAP]
8.1.1 TLVs carried within the PCED TLV
IANA is requested to manage sub-TLV types for the PCED TLV. IANA is requested to manage sub-TLV types for the PCED TLV.
Five sub-TLVs types are defined for this TLV and should be assigned Five sub-TLVs types are defined for the PCED sub-TLV and should be
by IANA: assigned by IANA:
-PCE-ADDRESS sub-TLV (suggested value = 1)
-PATH-SCOPE sub-TLV (suggested value = 2)
-PCE-DOMAINS sub-TLV (suggested value = 3)
-PCE-DEST-DOMAINS sub-TLV (suggested value =4)
-GENERAL-CAP sub-TLV (suggested value = 5)
-PATH-COMP-CAP sub-TLV (suggested value = 6)
Three sub-TLVs types are defined for the PCE-DOMAINS and PCE-DEST- Type Description Reference
DOMAINS TLVs and should be assigned by IANA:
-IPv4 area ID sub-TLV (suggested value = 1) 1 PCE-ADDRESS This document
-IPv6 area ID sub-TLV (suggested value = 2) 2 PATH-SCOPE This document
-AS number sub-TLV (suggested value = 3) 3 PCE-DOMAINS This document
4 PCE-DEST-DOMAINS This document
5 GENERAL-CAP This document
6 PATH-COMP-CAP This document
TLVs carried within the PCE-DOMAINS and PCE-DEST-DOMAINS TLV
Three TLVs types are defined for the PCE-DOMAINS and PCE-DEST-DOMAINS
TLVs and should be assigned by IANA:
Type Description Reference
1 IPv4 Area ID This document
2 IPv6 Area ID This document
3 AS number This document
TLV carried within the PATH-COMP-CAP sub-TLV
Three sub-TLV types are defined for the PATH-COMP-CAP TLV and should Three sub-TLV types are defined for the PATH-COMP-CAP TLV and should
be assigned by IANA: be assigned by IANA:
-Objective Functions sub-TLV (suggested value =1)
-Opaque Objective Function TLV (suggested value =2)
-Switch Caps sub-TLV (suggested value =3)
IANA will assign a new codepoint for the OSPF PCES TLV defined in Type Description Reference
this document and carried within the Router Information LSA.
IANA is requested to manage sub-TLV types for the PCES TLV. Two sub- 1 Objective Functions This document
TLVs types are defined for this TLV and should be assigned by IANA: 2 Opaque Objective Function This document
-PCE-ADDRESS sub-TLV (suggested value = 1) 3 Switch Caps sub-TLV This document
-CONGESTION sub-TLV (suggested value = 2)
8.1.2 TLVs carried within the PCES TLV
IANA is requested to manage TLV types for the PCES TLV.
Type Description Reference
1 PCE-ADDRESS This document
2 CONGESTION This document
8.2. Capability bits 8.2. Capability bits
IANA is requested to manage the space of the General Capabilities IANA is requested to manage the space of the General Capabilities
32-bit flag and the Path Computation Capabilities 32-bit flag defined 32-bit flag and the Path Computation Capabilities 32-bit flag defined
in this document, numbering them in the usual IETF notation starting in this document, numbering them in the usual IETF notation starting
at zero and continuing through 31. at zero and continuing through 31.
New bit numbers may be allocated only by an IETF Consensus action. New bit numbers may be allocated only by an IETF Consensus action.
Each bit should be tracked with the following qualities: Each bit should be tracked with the following qualities:
- Bit number - Bit number
- Defining RFC - Defining RFC
- Name of bit - Name of bit
Currently two bits are defined in the General Capabilities flag. Here Currently two bits are defined in the General Capabilities flag. Here
are the suggested values: are the suggested values:
-0: Support for Request prioritization. -0: Support for Request prioritization.
-1: Support for multiple messages within the same request message -1: Support for multiple messages within the same request message
Currently six bits are defined in the Path Computation Capabilities Currently seven bits are defined in the Path Computation Capabilities
flag. Here are the suggested values: flag. Here are the suggested values:
-0: Capability to handle GMPLS Constraints -0: Capability to handle GMPLS Constraints
-1: Capability to compute bidirectional paths -1: Capability to compute bidirectional paths
-2: Capability to compute link/node/SRLG diverse paths -2: Capability to compute link/node/SRLG diverse paths
-3: Capability to compute load-balanced paths -3: Capability to compute load-balanced paths
-4: Capability to compute a set of paths in a -4: Capability to compute a set of paths in a
synchronized Manner synchronized Manner
-5: Support for multiple objective function -5: Support for multiple objective function
-6: Capability to handle path constraints (e.g. hop count, metric -6: Capability to handle path constraints (e.g. hop count, metric
bound) bound)
9. Security Considerations 9. Security Considerations
Any new security issues raised by the procedures in this document Any new security issues raised by the procedures in this document
depend upon the opportunity for LSAs to be snooped, the depend upon the opportunity for LSAs to be snooped, the
ease/difficulty of which has not been altered. As the LSAs may now ease/difficulty of which has not been altered. As the LSAs may now
contain additional information regarding PCE capabilities, this contain additional information regarding PCE capabilities, this
new information would also become available. new information would also become available. Mechanisms defined to
secure OSPF LSAs [RFC2154], and their TLVs, can be used to secure the
PCED and PCES TLVs as well.
10. References 10. Manageability Considerations
10.1. Normative references Manageability considerations for PCE Discovery are addressed in
section 4.10 of [RFC4674].
11. Acknowledgments
We would like to thank Lucy Wong and Adrian Farrel for their useful
comments and suggestions.
12. References
12.1. Normative references
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78, RFC [RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78, RFC
3667, February 2004. 3667, February 2004.
[BCP79] Bradner, S., "Intellectual Property Rights in IETF [BCP79] Bradner, S., "Intellectual Property Rights in IETF
Technology", RFC 3979, March 2005. Technology", RFC 3979, March 2005.
[OSPF-v2] Moy, J., "OSPF Version 2", RFC 2328, April 1998. [OSPF-v2] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[OSPF-v3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", [OSPF-v3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6",
RFC 2740, December 1999. RFC 2740, December 1999.
[RFC2370] Coltun, R., “The OSPF Opaque LSA Option”, RFC 2370, July [RFC2370] Coltun, R., “The OSPF Opaque LSA Option”, RFC 2370, July
1998. 1998.
[OSPF-TE] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering [RFC3630] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
Extensions to OSPF Version 2", RFC 3630, September 2003. Extensions to OSPF Version 2", RFC 3630, September 2003.
[OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur, [OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur,
J.P., "Extensions to OSPF for advertising Optional Router J.P., "Extensions to OSPF for advertising Optional Router
Capabilities", draft-ietf-ospf-cap, work in progress. Capabilities", draft-ietf-ospf-cap, work in progress.
[RFC4655] Farrel, A., Vasseur, J.P., Ash, J., "Path Computation [RFC4655] Farrel, A., Vasseur, J.P., Ash, J., "Path Computation
Element (PCE)-based Architecture", RFC4655, August 2006. Element (PCE)-based Architecture", RFC4655, August 2006.
[PCE-DISCO-REQ] Le Roux, J.L., et al. "Requirements for PCE [RFC4674] Le Roux, J.L., et al. "Requirements for PCE discovery",
discovery", draft-ietf-pce-discovery-reqs, work in progress RFC4674, October 2006.
[RFC4203] Kompella, Rekhter, " OSPF Extensions in Support of [RFC4203] Kompella, Rekhter, " OSPF Extensions in Support of
Generalized Multi-Protocol Label Switching (GMPLS)", RFC4203, October Generalized Multi-Protocol Label Switching (GMPLS)", RFC4203, October
2005. 2005.
10.2. Informative references [RFC2154] Murphy, S., Badger, M., and B. Wellington, "OSPF with
Digital Signatures", RFC 2154, June 1997.
[PCECP-REQ] Ash, J., Le Roux, J.L., " PCE Communication Protocol 12.2. Informative references
Generic Requirements", draft-ietf-pce-comm-protocol-gen-reqs, work in
progress. [RFC4657] Ash, J., Le Roux, J.L., " PCE Communication Protocol
Generic Requirements", RFC4657, September 2006.
[PCEP] Vasseur et al., “Path Computation Element (PCE) communication [PCEP] Vasseur et al., “Path Computation Element (PCE) communication
Protocol (PCEP) - Version 1”, draft-ietf-pce-pcep, work in progress. Protocol (PCEP) - Version 1”, draft-ietf-pce-pcep, work in progress.
[ISIS-PCE-DISCO], Le Roux, Vasseur et la., "ISIS Extensions for PCE 13. Editor's Addresses:
Discovery", draft-ietf-pce-disco-isis, work in progress.
11. Authors' Addresses:
Jean-Louis Le Roux (Editor) Jean-Louis Le Roux (Editor)
France Telecom France Telecom
2, avenue Pierre-Marzin 2, avenue Pierre-Marzin
22307 Lannion Cedex 22307 Lannion Cedex
FRANCE FRANCE
Email: jeanlouis.leroux@orange-ft.com Email: jeanlouis.leroux@orange-ftgroup.com
Jean-Philippe Vasseur (Editor) Jean-Philippe Vasseur (Editor)
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts avenue 1414 Massachusetts avenue
Boxborough , MA - 01719 Boxborough , MA - 01719
USA USA
Email: jpv@cisco.com Email: jpv@cisco.com
14. Contributors' Addresses:
Yuichi Ikejiri Yuichi Ikejiri
NTT Communications Corporation NTT Communications Corporation
1-1-6, Uchisaiwai-cho, Chiyoda-ku 1-1-6, Uchisaiwai-cho, Chiyoda-ku
Tokyo 100-8019 Tokyo 100-8019
JAPAN JAPAN
Email: y.ikejiri@ntt.com Email: y.ikejiri@ntt.com
Raymond Zhang Raymond Zhang
BT Infonet BT Infonet
2160 E. Grand Ave. 2160 E. Grand Ave.
El Segundo, CA 90025 El Segundo, CA 90025
USA USA
Email: raymond_zhang@infonet.com Email: raymond_zhang@infonet.com
12. Intellectual Property Statement 15. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
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made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 24, line 37 skipping to change at page 25, line 20
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
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Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject Copyright (C) The IETF Trust (2006). This document is subject to the
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